This invention relates to a system of recording and reproducing an electric charge image.
Since image signals obtained by electronic image-taking an object have such advantageous features that the image signals are easily handled to edit, trimming and other picture image processings and also to reproduce and erase the records, the image signals are widely used in such fields as printing, electronic printing and measuring. Consequently, it has been strongly desired to develop a device which enables photographing and recording a moving picture which requires to obtain optical image informations corresponding to a plurality of times, as well as a device capable of photographing and recording a single picture image at a higher resolution than a prior art device.
In a conventional image pick-up device utilizing an image pick-up tube as an image pick-up element, since there is a limit for down-sizing the electron beam diameter of the image pick-up tube it is impossible to realize a high degree of resolution by reducing an electron beam diameter. Moreover, since the target capacity of the image pick-up tube increases as the target area increases, it has been impossible to obtain a high degree of resolution by increasing the target area. Further, in a case of an image pick-up device of a moving picture, for example, since the frequency band of the image signals ranges from several tens MHz to higher than several hundreds MHz, the S/N ratio presents a problem. For the reasons described above, it has been difficult to produce such image signal reproduced from a picture image of a high picture quality and a high resolution. Accordingly, it has been strongly desired to obtain an image pick-up device capable of efficiently producing an image signal reproduced from a picture image of a high picture quality and a high resolution.
With increasing requirement for recording various information signals at a high recording density, in recent years, high density recording and reproducing devices have been developed capable of high density recording and reproducing an information signal by using a recording medium operating with various constructions and functions. For example, various devices have been proposed including pit forming type, foam or irregular shape type, magneto-optical type, phase transfer type, heat transition type (wherein light transmissibility, percentage of reflection, percentage of absorption, etc. are caused to vary by heat energy). Furthermore, a device utilizing a recording medium wherein recording and reproducing operations are effected by an energy other than a light energy and a recording and reproducing device utilizing such medium have also been proposed.
We have also proposed various devices in which an optical image information corresponding to an optical image of an object to be photographed is focused on a reversible charge image recording medium through an image pick-up lens so as to record and reproduce an information to be recorded and reproduced in and from a charge image recording medium or a device capable of recording and reproducing an information to be recorded on a charge image recording medium as a charge image having a high resolution.
These devices could record an electromagnetic radiation information to be recorded on the charge image recording medium as a charge image having a ultra high resolution. However, the reading out of the charge image having the ultra high resolution and recorded on the charge image recording medium has been effected by using an electrostatic voltage detecting means which takes (or reads) out a voltage created by electrostatic induction in a detection electrode in an electric field formed by a charge image or by disposing an optical read out head containing photo-modulation member and positioned in an electric field created by the charge image, thereby optically detecting the charge image stored on the charge image recording medium, so that where the electrostatic voltage detecting means or the optical read out head is used it is not always possible to produce such information signal that ensures a reproduced image of a high resolution.